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Identity HelpIdentifying Petalite Vs Rose Quartz

20th Sep 2017 02:02 UTCThe Walking Rock

Hello

I am unable to do any physical / chemical testing with it but something is telling me that this is not rose quartz but pink Petalite. Are there any specific visual aspects to pink Petalite?

I attached images of different polished point & Spheres. what do you think?

20th Sep 2017 02:23 UTCPaul Brandes 🌟 Manager

Shouldn't be that hard to test....

Find yourself a piece of Quartz and see if it scratches the "Petalite".

Petalite is slightly softer than Quartz.

20th Sep 2017 02:24 UTCThe Walking Rock

-- moved topic --

20th Sep 2017 03:31 UTCDoug Daniels

The first photo seems a bit big for petalite. The other two, maybe, but still.

20th Sep 2017 05:23 UTCVolkmar Stingl

Hardness: petalite about 6.2, quartz 7

Spec. weight: petalite about 2.42, quartz 2.63

Like Paul said: Should be easy to determine.

20th Sep 2017 13:14 UTCReiner Mielke Expert

Petalite has a perfect cleavage. I see nothing in the samples shown that indicate a perfect cleavage.

20th Sep 2017 14:02 UTCThe Walking Rock

Thanks, I will visit the guy and see if I can do the "scratch" test. I noticed that there are some rough pieces of petaline (no perfect cleavage) which would look similar to the images above once polished. Don't you think? I saw 1001 rose quartz spheres, points, etc and there is a shine in there and a "detailed structure" which I never came across before. Also I am short on ideas what kind of crystal the first point could be. The chaotic structure in it doesn't ring any bells in me .

20th Sep 2017 14:25 UTCThe Walking Rock

and this one, Petalite from Namibia

20th Sep 2017 18:36 UTCOwen Lewis

Hi Volkmar,

Volkmar Stingl Wrote:

-------------------------------------------------------

> Hardness: petalite about 6.2, quartz 7

The Mohs numbers should be more properly thought of as a list of 10 specified minerals, arranged, 1 to 10, in order of what will scratch all the minerals numbered below it in the list. If one calls it a scale (as we all do) then it is important to remember that the values in the scale are irrational, in that there is no unit of measurement applied; the difference between 9 and 10 is not the same as the difference between 9 and 8 or 2 and 1. And what of kyanite which can return a Mohs number of 4, 5, 6 or 7. In such a context what can 6.2 mean? in what way is meaningfully different from 6.1 or 6.4?

> Spec. weight: petalite about 2.42, quartz 2.63

Quartz 2.65 (+/- 0.01)? 2.63 should be good only for chalcedony which, unlike clean quartz, does not have a really tight (empiric) SG value.

@ TWR,

Your wand looks polycrystalline to me. Possibly an assemblage of chips in a resin binding? If you haven't an FTIR spectroscope handy, take a really careful SG?

21st Sep 2017 01:12 UTCDonald B Peck Expert

Owen, I completely agree with you on the Mohs "Scale". Half values are used to indicate "between", but other fractional values should not be used. If more accurate and precise values are needed, then a Vin microindentation instrument, or something similar, should be used. And not many of us have access to those.

As to directionallity. As I am sure you know, all minerals exhibit different hardnesses in different crystallographic directions and on different forms. For most the difference is very small, unlike for kyanite.

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